My guess is it will be a magic keyboard with a touch bar on top that comes with a new iMac. We will likely see it in April the earliest or more likely WWDC in early June. Or they may even make us wait until next October.
My source for this? My deep-seated confidence in my own ability to make guesses about stuff and be right. Lol
I would agree, if it wasn't for the fact that the touch bar looks like a generic display (it can do custom controls for Final Cut and Photos). That's not going to be friendly to Bluetooth bandwidth. Nor battery.
Hell, I might actually want one. But the reality is that I'm not entirely sure the wireless tech is *quite* where it needs to be for this yet. And I am also a bit curious if Apple would go back to wired to make this work. A laptop makes the most sense since the keyboard is integrated, so you can sip from a larger battery, and not worry about bandwidth/latency to the display.